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How to Declare, Create, and Call a Method in C#?

In C#, a method can be a function or a procedure (subroutine). A method has a name, and a body contains the sequence of statements to be executed when the method is called. In this tutorial, you will learn how to declare, create, and call a method in C# with examples.

Important Notes

  1. C# does not support global methods; methods should be written in a class; otherwise, you will not be able to compile the code.
  2. You must specify the types of parameters and the type of return value.
  3. A method that returns a value is a function, and a method that does not return any value is a procedure (subroutine).

C# - Declare a Method

In C#, the syntax of declaring a method is as follows:

[returnType | void] methodName (parameterList separated with comma)
{
   // sequence of statements
   [return expression;]
}

Here are the details of the elements that make up a declaration:

  • The returnType is the name of the data type that the method will return. This can be any type such as string, or int. If a Method does not return a value, then void keyword should be used in the place of the return type.
  • The methodName is the name of the method. Rules should be followed for method name same as variable names in C#. It is better to follow the camelCase convention for method names, for example, processData.
  • The parameterList, parameters are optional but if a method requires parameters then describe its type and name. Parameters should be written in the brackets () and should be separated with a comma if more than one.
  • The Curly Braces, method code, should be inside the curly braces {}.
  • The return expression will be used if you are creating a method that returns a value. If a method that does not returns a value, means created as void then no need to use the return statement.

C# - Create a Method

The following is an example of a method that returns a value (function). It accepts two parameters and will sum up the value and return.

int sumValues(int aNumber, int bNumber)
        {
            int nResult;
            nResult = aNumber + bNumber;
            return nResult;
        }

Below is an example of a method that does not return a value (procedure).

void printText (string sName)
{
     Console.WriteLine($"Hello {sName}");
}

C# - Calling a Method

The following are the examples of calling a method in C#:

int a = 5;
int b = 9;
int t;
t = sumValues(a, b);
printText("World");

Here is the complete example for methods. In the following C# program, two methods are created in the class Program; one is sumValues a function type method which returns the total of the two numbers given in the parameters and the second is the printText, a procedure type method which prints the Hello followed by the name given in the parameter.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace CreatingMethods
{
    class Program
    {
        int sumValues(int aNumber, int bNumber)
        {
            int nResult;
            nResult = aNumber + bNumber;
            return nResult;
        }
        void printText (string sName)
        {
            Console.WriteLine($"Hello {sName}!");
        }
        static void Main(string[] args)
        {
            // calling method sumValues
            Program myMethods = new Program();

            int nTotal = myMethods.sumValues(5, 9);
            Console.WriteLine("The total of 5 + 9 is " + nTotal);

            // calling method printText

            myMethods.printText("World");
        }
    }
}

Output

The total of 5 + 9 is 14
Hello World!
Press any key to continue . . .

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